<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    *{
        margin: 0;
        padding: 0;
        box-sizing: border-box;
    }
    .box{
        width: 450px;
        height: 500px;
        background-color: skyblue;
        margin:  20px auto;
        border-radius: 10px;
    }
    .input{
        width: 90%;
        height: 60px;
        background-color: gold;
        margin: 10px auto;
    }
    .input > input{
        width: 100%;
        height: 100%;
        outline: none;
        border: none;
        font-size: 28px;
    }
    .keystroke{
        display: flex;
        width: 100%;
        height: 360px;
        margin-top: 10px;
    }
    .left{
        width: 90px;
        height: 100%;
        background-color: tomato;
        /* padding: 10px; */
    }
    .right{
        flex: 1;
        background-color: lawngreen;
    }
    </style>
</head>
<body>
    <div class="box">
        <div class="input">
            <input type="text" id="numeral">
        </div>
        <div class="keystroke">
        <div class="left"></div>
        <div class="right"></div>
        </div>
    </div>
</body>
</html>